An adaptor for discriminating connection of an oral tip having a length greater than 0.50 (12.70 mm) to a feeding line and for preventing sealed connection with a standard semi-rigid luer tip having a length less than or equal to 0.50 in (12.70 mm) is disclosed. The adaptor includes a duckbill valve spaced at least 0.50 in (12.70 mm) downstream from a first open end of the body such that when an oral tip is fully inserted into a connection port, the oral tip engages valve flaps of the duckbill valve and opens the valve, and when a standard semi-rigid luer tip is fully inserted into the connection port, the standard semi-rigid luer tip does not contact the valve flaps and the valve flaps remain in a closed position.